1. Field
The invention relates to sterilizers of the type used in the fields of medicine, dentistry and biological sciences. It is particularly directed to the vent stream (emissions) from such sterilizers and provides an exhaust (vent) filter system of general application but of particular use with chemical vapor sterilizers.
2. State of the Art
The potential health hazards associated with the discharge of exhaust emissions from sterilizer systems and apparatus are well recognized. Chemical vapor sterilization, as widely practiced, involves the exposure of biologically contaminated articles to chemical vapors in a sterilization chamber. At the termination of the sterilization procedure, the vapors are collected and reclaimed, but traces of potentially harmful vapors and/or gases may remain in the chamber and its contents.
It has been the practice in large-scale equipment to purge the chamber of such residual vapors by directing a stream of air or other purge gas, such as nitrogen, through the chamber. The residual chemical sterilant is thereby swept from the chamber in an exhaust or vent stream. The vent stream is composed of fluids, composed primarily of gases, but often including vaporous constituents which tend to condense upon cooling. More recently, purging is practiced in smaller scale equipment as well.
Particularly in the case of smaller scale sterilization equipment, discharge of the vent stream may be directly into the interior of a room. If the room is small and poorly ventilated, the possibility exists that unacceptable levels of chemical irritants, e.g. formaldehyde, may accumulate in the room over a prolonged period. One expedient for reducing or eliminating this possibility is to filter or chemically neutralize the vent fluids prior to their discharge into the atmosphere. The presence of condensible vapors in the vent fluids interferes with such procedures. Condensation blocks filter passages and accelerates deterioration of many filter media Moreover, proper maintenance and replacement of filters, while essential, has not been reliably practiced, largely due to inadequate monitoring procedures.
There remains a need for an improved exhaust filter system for chemical and other sterilizer systems.